A couple of years ago, a similar request was raised here: Support policy for previous releases.
Does grafana have a support policy documented anywhere? i.e how many versions back it’ll maintain?
If I were to guess, looking at the release tags:
It looks like around 3 at a given time? i.e the highest version right now is v3.1.1, but there was a v3.0.1 release cut most recently, and v2.9/10 was cut recently too.